Comparative study of the tarnishing resistance of several coloured base gold alloys

The stability of coloured gold alloys may be dependent on the environment that involves them. This paper is concerned with the effect of an artificial sweat solution in the stability of several gold base alloys with different colours. The changes in the samples physical properties, colour, brightness, and reflectance were measured for several periods of immersion. Two types of alloys (purple and blue coloured alloys) showed to be sensitive to the artificial sweat solution. The other tested alloys have a high resistance to tarnishing comparable with the results obtained for pure gold

Predictive Representations: Building Blocks of Intelligence

Adaptive behavior often requires predicting future events. The theory of reinforcement learning prescribes what kinds of predictive representations are useful and how to compute them. This review integrates these theoretical ideas with work on cognition and neuroscience. We pay special attention to the successor representation and its generalizations, which have been widely applied as both engineering tools and models of brain function. This convergence suggests that particular kinds of predictive representations may function as versatile building blocks of intelligence

Experimental analysis on steel reinforced glass beams at different temperatures

This work is funded by FEDER Funds, through the Operational Programme Competitiveness Factors – COMPETE, and Portuguese Funds, through FCT - Foundation for Science and Technology, under the project PTDC/ECM/116609/2010, “S-GLASS: Structural Performance and Design Rules of Glass Beams Externally Reinforced”. In addition, The COST Action TU0905 ‘‘Structural Glass – Novel Design Methods and Next Generation Products’’ is also acknowledged.Whereas glass components were used as infill elements in the past, contemporary architectural concepts include glass components as load-bearing elements. Recent architectural trends and technological developments have brought about unprecedented opportunities in the use of glass in buildings. The increasingly daring structural applications of glass will continue to drive the development of structural glass elements with high post-failure resistances. The present work aims to explore the concepts of structural performance of glass beams and the effectiveness of an embedded steel reinforcement system. The reinforcement system consists in embedding perforated stainless steel plates in the lamination process. The experimental study focuses on the effect of thermal actions and compares the use of soft foils and stiff foils (temperature ranging from approximately 16 ºC to 85 ºC).Fundação para a Ciência e a Tecnologia (FCT

Automatic subject-based contextualisation of programming assignment lists.

As programming must be learned by doing, introductory programming course learners need to solve many problems, e.g., on systems such as ’Online Judges’. However, as such courses are often compulsory for non-Computer Science (nonCS) undergraduates, this may cause difficulties to learners that do not have the typical intrinsic motivation for programming as CS students do. In this sense, contextualised assignment lists, with programming problems related to the students’ major, could enhance engagement in the learning process. Thus, students would solve programming problems related to their academic context, improving their comprehension of the applicability and importance of programming. Nonetheless, preparing these contextually personalised programming assignments for classes for different courses is really laborious and would increase considerably the instructors’/monitors’ workload. Thus, this work aims, for the first time, to the best of our knowledge, to automatically classify the programming assignments in Online Judges based on students’ academic contexts by proposing a new context taxonomy, as well as a comprehensive pipeline evaluation methodology of cutting edge competitive Natural Language Processing (NLP). Our comprehensive methodology pipeline allows for comparing state of the art data augmentation, classifiers, beside NLP approaches. The context taxonomy created contains 23 subject matters related to the non-CS majors, representing thus a challenging multi-classification problem. We show how even on this problem, our comprehensive pipeline evaluation methodology allows us to achieve an accuracy of 95.2%, which makes it possible to automatically create contextually personalised program assignments for non-CS with a minimal error rate (4.8%)

Influence of ultrasound stimulation on the viability, proliferation and protein expression of osteoblasts and periodontal ligament fibroblasts

Among the adjunctive procedures to accelerate orthodontic tooth movement (OTM), ultrasound (US) is a nonsurgical form of mechanical stimulus that has been explored as an alternative to the currently available treatments. This study aimed to clarify the role of US in OTM by exploring different stimulation parameters and their effects on the biological responses of cells involved in OTM. Human fetal osteoblasts and periodontal ligament fibroblasts cell lines were stimulated with US at 1.0 and 1.5 MHz central frequencies and power densities of 30 and 60 mW/cm2 in continuous mode for 5 and 10 min. Cellular proliferation, metabolic activity and protein expression were analyzed. The US parameters that significantly improved the metabolic activity were 1.0 MHz at 30 mW/cm2 for 5 min and 1.0 MHz at 60 mW/cm2 for 5 and 10 min for osteoblasts; and 1.0 MHz at 30 mW/cm2 for 5 min and 1.5 MHz at 60 mW/cm2 for 5 and 10 min for fibroblasts. By stimulating with these parameters, the expression of alkaline phosphatase was maintained, while osteoprotegerin synthesis was induced after three days of US stimulation. The US stimulation improved the biological activity of both osteoblasts and periodontal ligament fibroblasts, inducing their osteogenic differentiation.This in vitro study was supported by FCT (Fundação para a Ciência e Tecnologia) in the scope of the grants UI/BD/150951/2021 and UI/BD/09375/2020, the funding contract 2020.00215.CEECIND (DOI: 10.54499/2020.00215.CEECIND/CP1600/CT0009) and through the projects UIDB/04436/2020, UIDP/04436/2020, FunFibRai—PTDC/EME-EME/4197/2021 (DOI: 10.54499/PTDC/EME-EME/4197/ 2021), BrainStimMap—PTDC/EME-EME/1681/2021 (DOI: 10.54499/PTDC/EME-EME/1681/2021), AlignAgen-GI2-CESPU-2022 and UID/CTM/00264/2021 project of 2C2T under the COMPETE and FCT/MCTES (PIDDAC), co-financed by FEDER through the PT2020 program

Optimization of a photobiomodulation protocol to improve the cell viability, proliferation and protein expression in osteoblasts and periodontal ligament fibroblasts for accelerated orthodontic treatment

Numerous pieces of evidence have supported the therapeutic potential of photobiomodulation (PBM) to modulate bone remodeling on mechanically stimulated teeth, proving PBM's ability to be used as a coadjuvant treatment to accelerate orthodontic tooth movement (OTM). However, there are still uncertainty and discourse around the optimal PBM protocols, which hampers its optimal and consolidated clinical applicability. Given the differential expression and metabolic patterns exhibited in the tension and compression sides of orthodontically stressed teeth, it is plausible that different types of irradiation may be applied to each side of the teeth. In this sense, this study aimed to design and implement an optimization protocol to find the most appropriate PBM parameters to stimulate specific bone turnover processes. To this end, three levels of wavelength (655, 810 and 940 nm), two power densities (5 and 10 mW/cm2) and two regimens of single and multiple sessions within three consecutive days were tested. The biological response of osteoblasts and periodontal ligament (PDL) fibroblasts was addressed by monitoring the PBM's impact on the cellular metabolic activity, as well as on key bone remodeling mediators, including alkaline phosphatase (ALP), osteoprotegerin (OPG) and receptor activator of nuclear factor κ-B ligand (RANK-L), each day. The results suggest that daily irradiation of 655 nm delivered at 10 mW/cm2, as well as 810 and 940 nm light at 5 mW/cm2, lead to an increase in ALP and OPG, potentiating bone formation. In addition, irradiation of 810 nm at 5 mW/cm2 delivered for two consecutive days and suspended by the third day promotes a downregulation of OPG expression and a slight non-significant increase in RANK-L expression, being suitable to stimulate bone resorption. Future studies in animal models may clarify the impact of PBM on bone formation and resorption mediators for longer periods and address the possibility of testing different stimulation periodicities. The present in vitro study offers valuable insights into the effectiveness of specific PBM protocols to promote osteogenic and osteoclastogenesis responses and therefore its potential to stimulate bone formation on the tension side and bone resorption on the compression side of orthodontically stressed teeth.This research was supported by FCT (Fundação para a Ciência e Tecnologia) in the scope of the grants UI/BD/09375/2020 and UI/BD/150951/2021, and through the projects UIDB/04436/2020 and UIDP/04436/2020. Additional national funds were provided by FCT under the scope of the projects Stimcart (doi: 10.54499/PTDC/EME-EME/4520/2021), FunFibRAI (doi: 10.54499/PTDC/ EME-EME/4197/2021), and BrainStimMap (doi: 10.54499/PTDC/EME-EME/1681/2021), as well as through the contract 2020.00215.CEECIND (doi: 10.54499/2020.00215.CEECIND/CP1600/CT0009). Finally, funding was also given by CESPU—Cooperativa de Ensino Superior Politécnico e Universitário, in the scope of the project AlignAgen-GI2-CESPU-2022

Roadmap on semiconductor-cell biointerfaces.

This roadmap outlines the role semiconductor-based materials play in understanding the complex biophysical dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mechanical devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biological components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biological world

Determinants of bone mineral density in post-menopause

Pós-menopausa é período de maior perda óssea e faz-se necessário instituir medidas preventivas que amenizem sua progressão. Objetivo: correlacionar o escore da densidade mineral óssea (DMO) e seus fatores de risco, buscando determinar aqueles que mais a influenciam. Método: estudo transversal, descritivo de 62 mulheres na pós-menopausa, saudáveis, idade média de 56,82 ± 4,02 anos, avaliadas quanto aos fatores de risco para osteoporose e nível de atividade física. Absorção de dupla energia de raios-X (DXA) avaliou coluna lombar e fêmur proximal. Os grupos, DMO normal e diminuída, foram analisados pelos testes T de Student, qui-quadrado e correlações. Resultados: Mulheres com menor índice de massa corporal (IMC), maior idade e maior tempo de menopausa apresentaram menor DMO em fêmur. Raça negra e ausência de história familiar correlacionaram-se com maior DMO. Conclusão: IMC, idade, peso, história familiar de osteoporose, raça e tempo de menopausa foram os principais fatores determinantes da DMO em mulheres na pós-menopausaPost-menopause is the period of greatest bone loss and it is necessary to introduce preventative measures to mitigate its progression. Aim: compare the score of bone mineral density (BMD) and their risk factors and to determine those most influencing. Method: Cross-sectional, descriptive study of 62 postmenopausal women, healthy, average age 56.82 ± 4.02 years, evaluated for risk factors for osteoporosis and physical activity level. Absorption dual energy X-ray absorptiometry (DXA) evaluated lumbar spine and proximal femur. Groups, normal and reduced BMD were analyzed by Student’s t test, chisquare and correlations. Results: Women with lower body mass index (BMI), older age and longer duration of menopause had lower BMD at the femur. Black race and absence of family history correlated with higher BMD. Conclusion: BMI, age, weight, family history of osteoporosis, race, and time since menopause were the main determinants of BMD in postmenopausal wome

Inconsistency in shoulder arthrometers for measuring glenohumeral joint laxity: a systematic review

There is no consensus on how to measure shoulder joint laxity and results reported in the literature are not well systematized for the available shoulder arthrometer devices. This systematic review aims to summarize the results of currently available shoulder arthrometers for measuring glenohumeral laxity in individuals with healthy or injured shoulders. Searches were conducted on the PubMed, EMBASE, and Web of Science databases to identify studies that measure glenohumeral laxity with arthrometer-assisted assessment. The mean and standard deviations of the laxity measurement from each study were compared based on the type of population and arthrometer used. Data were organized according to the testing characteristics. A total of 23 studies were included and comprised 1162 shoulders. Populations were divided into 401 healthy individuals, 278 athletes with asymptomatic shoulder, and 134 individuals with symptomatic shoulder. Sensors were the most used method for measuring glenohumeral laxity and stiffness. Most arthrometers applied an external force to the humeral head or superior humerus by a manual-assisted mechanism. Glenohumeral laxity and stiffness were mostly assessed in the sagittal plane. There is substantial heterogeneity in glenohumeral laxity values that is mostly related to the arthrometer used and the testing conditions. This variability can lead to inconsistent results and influence the diagnosis and treatment decision-making.This article is a result of the project DILATO (reference 47289) supported by the Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF)